@testable import PureYAML
import Testing

/// The reader-level control-character check (`Reader.recordFirstInvalidControlCharacter`,
/// `fetchNextToken()`'s check in `LibYAML.Scanner.Fetch.swift`) added to close a real gap
/// found comparing PureYAML against Yams on a real-world OpenAPI corpus: Yams's underlying
/// libyaml rejects raw control characters (`c-printable` violations) anywhere in the input,
/// while `PureYAML.parse()` previously accepted them silently (the only existing check,
/// `PreflightScanner.invalidControlCharacterColumn`, is opt-in via `validate()`, not part of
/// the core scanner `parse()` uses).
@Suite("Invalid control character rejection")
struct InvalidControlCharacterTests {
    @Test("A raw control character in scalar content is rejected with the correct position")
    func test_rawControlCharacterRejected() {
        expectParseError(
            "key: value\u{01}with control\n",
            .invalidControlCharacter(line: 1, column: 11),
        )
    }

    @Test("A tab in scalar content, not indentation, is still legal")
    func test_tabInContentStillAccepted() throws {
        let value = try PureYAML.parse("key: value\twith tab\n")
        let mapping = requireMapping(value)
        #expect(mapping?["key"] == .string("value\twith tab"))
    }

    @Test("CR and LF are still legal")
    func test_crAndLFStillAccepted() throws {
        let value = try PureYAML.parse("key: |\n  line one\n  line two\n")
        let mapping = requireMapping(value)
        #expect(mapping?["key"] == .string("line one\nline two\n"))
    }

    @Test("A control character deep inside a large document is still caught")
    func test_controlCharacterFarIntoDocumentIsCaught() {
        let padding = String(repeating: "line: value\n", count: 5000)
        expectParseError(
            padding + "bad: value\u{02}here\n",
            .invalidControlCharacter(line: 5001, column: 11),
        )
    }

    @Test("An earlier real syntax error is not hidden behind a later control character")
    func test_earlierSyntaxErrorNotHiddenByLaterControlCharacter() {
        do {
            _ = try PureYAML.parse("key: \"unterminated\nbad: value\u{02}here\n")
            recordIssue("expected parse to throw")
        } catch let error as PureYAML.Parsing.ParseError {
            #expect(error.diagnosticCode != "invalidControlCharacter")
        } catch {
            recordIssue("expected a ParseError, got \(error)")
        }
    }
}